1. Field of the Invention
The present invention relates to a centrifugal clutch comprising a driving plate secured to an input shaft operatively connected to a driving source, a cylindrical bottomed drum detachably secured to an end, projecting from the input shaft, of an output shaft concentrically and relatively rotatably disposed within the input shaft, the cylindrical bottomed drum surrounding the driving plate, and a clutch spring connected to each of a plurality of shoes supported on the drum for movement toward and away from an inner peripheral surface of the drum respectively by a plurality of stub shafts parallel to the input shaft, the clutch spring providing a spring force in a direction away from the inner peripheral surface of the drum.
2. Description of the Prior Art
In such centrifugal clutch, it is conventionally common to arrange shoes and clutch springs on one side of the driving plate (for example, see Japanese Utility Model Application Laid-open No. 43647/74).
Such centrifugal clutch is usually utilized in motorcycles of a smaller stroke volume or the like in combination with a V-belt type continuously variable transmission, but an attempt has been made to apply this type of clutch to a vehicle of larger stroke volume because of an ease of operation thereof. In this case, it is necessary to increase the clutch capacity of the centrifugal clutch.
To increase the clutch capacity, it is considered to increase the weight of a shoe; to increase the number of shoes; or to increase its entire effective diameter.
However, if the weight of a shoe is increased, it is required to enhance the rigidity of the driving plate and the drum so that they can meet an increase in centrifugal force corresponding to such increase in weight of the shoe, and consequently, the entire weight must also increase. Moreover, it is also necessary to increase the spring load of the clutch spring following the increase in shoe weight, and this causes a difficulty in setting the spring load.
To increase the number of shoes for meeting the requirement, there is a limitation in space for the number of shoes mountable on the driving plate and hence, increasing the number of shoes is impossible in many cases.
Further, there are also a lot of limitations in space for increasing the entire effective diameter and it is impossible in many cases.